Broach sharpening machine



Nov. 13, 1945o H. H. G01-BERG 2,3;3735

BROACH SHARPENING MCHINE Filed March 24, 1943 s' sheets-sheet 1 ATTORNEYS.

Nov. 13, 1948. H. HGTBERG 2,388,785

BROACH SHARPENING MACHINE 29M@ wiz@ ATTORNEYS.'

Nov. 13, 1945. H. H. GOTBERG 2,388,785

BROACH SHARPENING MACHINE 4 Filed March 24, 1943 6 Sheets-Sheet 4 INVENTOR AITORNEYS.

Nov. 13, 1945. H. H. GOTBERG BROACH SHARPENING MACHINE 6 'Sheets-Sheet 5 Filed March 24, 1943 INVENTOR Harry #j Gazefg BY ATTORNEYS- NOV. 13, 1945. H H, GOTBERG 2,388,785

BROACH SHARPENING MACHINE Filed March 24, 1945 6 Sheets-Sheet 6 INVENTOR /L/df' a er BY "g g ATTORNEYS- v.its operation; and

Patented Nov. lf3, 1945 T *ori-ica 4 BBOACB SHARPENING MACHINE Harry H. Gotberg, Detroit, Mich., assigner to Colonial Breach Comp poration of Delaware any, Detroit, Mich., a oor- Aspucsaon Maron 24, 1943, sani Naisos' A s claims. (ci. isi- 131) l erally at i4, by means of'which'the center l2 The present invention relates' to a broach sharpeningmachine.

In the past it has been found necessary to sharpen round and surface broaches on two different types of machines-one for each type of brooch-because of the differences in the manner in which the grinding lwheel must be adlusted and manipulated in sharpening the two types.A

The general object of the present invention is to provide a universal broach sharpening machine adapted to sharpen both round' and surface broaches.

It is another object of the present invention to lprovide a single machine which may be employed in sharpening 4both types of breaches and in which the manipulations required of the operator in sharpening each type of broach are the same as they are in the prior machines.

Other objects and advantages of the inventio will become apparent from the following specication, the accompanying drawings and the appended claims.

In the drawings, in which like numerals are used to designate like parts in the several views throughout:

Figure 1 is a fragmentary front view of the mal 5-5 or Figure 4; Y

Figure 6 is a fragmentary sectiontaken on the line B-B of Figure 4;

Figure 7 is a horizontal section taken on the line 'l-l of Figure 4;

Figure 8 is a fragmentary front elevation of the machine, showing the hand wheels for contro section Ytaken on the Figure 9 is a fragmentary transverse section gearing for moving the work slide.

and the dog I5 may be rotated in order to rotate 1 the breach during the sharpening operation. Thel a suitable chuck, such asthe magnetic chuck I8.-

illustrated in Figure 2.

Themachine is provided at the rear thereof with a vertical slide guided'and supported in suitable ways 2l on the base lll, as best shown in Figures 3 and 7. Vertical slide 20 is hollow and is open at its forward face, as best shown in Figure 4, in order to permit a gear. housing 24, which is fixed to the rear wall of the base l0, to project` into the slide without interfering with vertical movements of the slide'.

As best shown in Figures 4 and 7, the gear nousing 24 supports two pairs of worm and worm wheel. drive units. One of these units includes the worm 25 mounted upon a hollow shaft 24 journaled in suitable ball bearings 2l. The warm 25 meshes with a worm wheel 28 xed to a vertical shaft 29, which projects downwardlythrough a bs 30 in the under side of the gear housing 24. In the boss are positioned a pair of bearing sleeves 3| for Journaling the shaft. A collar 32 on shaft` 29 co-operates with the worm wheel 2B, the boss 30 and a pair of roller thrust bearings 32 to hold the shaft 29 against axial movement with respect to the gear housing. The lower end of shaft 2B is threaded into a sleeve 34 positioned Awithin a suitable bearing block fixed to the forward face of the vertical slide 20. Ag the resuit of this arrangement. rotation of the shaft 28 Y will cause the vertical slide to' move up or down with respect to the base Ill of the machine.

The second worm wheel unit includes a worm 40 axially aligned with the worm 25 and mounted upon a hollow shaft 4I journaled in suitable roller bearings 42. The worm 49 meshes with the worm wheel 44, fixed to e. vertical sleeve 45. The sleeve is journaled in a boss 4B in the under side of the gear housing 24 by means of a pair of bearing Referring to the drawings, and particularly to Figures 1 to 3, the machine comprises a main base A I0 having a horizontally movable work slide Il supported on ways in any suitable manner. The work supporting slide l l is adapted to support a pair of conventional centers l2 and I3 for rotatablysupporting a round brosch in the mannerv shown best in Figure 1.` center I2is part of a motor driven spindle mechanism indicated gensleeves 4l.' The lower end of the sleeve 4l is provided with a flange 49 which, together with the gear 44, the boss 48' and a pair of bali thrust bearings 48, holds the sleeve against axial move ment with respect to the gear housing.

'Ihe sleeve 45 is provided with an internal axial splined opening which slidably receives asplined shaft 50. The position of the shaft 50 with respect to the vertical slide 20 is controlled by a lever 52 having a yoke which engages between the flanges of a spool .53 threaded on a reduced portion at the lower end of shaft 50. The spoolis locked in position by means of a nut Il.' 52 is fixed to a shaft 55, which projects from the side of the verticalslide 20 and carries a lever 58. Blidably mounted in the end of lever 50 is a handie 51 which is secured to a spring pressed detent 58, adapted .to enter a pair of arcuately spaced openings' 58 in the side of the vertical slide 20 in order to hold the lever 50 and, consequently, the shaft 58 in adjusted position.

The upper end of the vertical slide 20V is pro`. vided with a central hollow cylindrical post 80 surrounding which is an horizontally disposed annular surface adapted to rotatably support v a rotary table u. secured to the rotary table V at its under side is an annular ring 55, whichl slidably engages the annular surface 8l. The

` rotarytable Il is provided with a vertical openliever-v ing l0 in which the cylindrical projection 80 of the vertical slide is journaled. As a result of this arrangement, it is 'apparent that the table is supported for rotation with respect to the vertical slide about a vertical axis.

The upper end of the previously described vertical shaft 50 projects through the cylindrical projection 00, and a sleeve 88 journaled on the shaft 50 likewise projects through the cylindrical projection 80. The upper end of the sleeve 68 is provided with a flange 88 which fits a recess in the upper surface of the table: and the lower end of the sleeve 88 is provided with a nut 10 threaded on the sleeve.

The nut 10 takes the form of a worm wheel that meshes with a worm 1| fixed to a horizontal shaft 'l2 which projects through one side of the vertical slide 20 and carries a handle 13 by means of which the shaft may.

be manually rotated. It will be apparent that, on rotation of the handle 18 inthe proper direction, worm wheel 18 will be threaded upon the sleeve 58. Since the upper surface of the worm wheel 10 bears against a downwardly projecting boss 15 in the upper end of the vertical slide 28,

this threading action will clamp the rotary table 8l against the annular surface 8| This clamping action may be adjusted to such a degree that the rotary table cannot turn.

The upper end of shaft 50 carries a pinion80 adapted to mesh with a rack 8| fixed in any suitable manner to a horizontal slide 82. As best is supported upon a pair of roller chains 83, each of which surrounds a horizontal laterally proiecting rib 84 formedjon the upper portion of the rotary tablel 6I. The ribs 8f extend parallel to each other and lie on opposite sides of the e Each roller chain forms a complete closed loop, with the result that cylindrical projection 50.

- shown in Figures 4 and 5, the horizontal slide 82 the rotary table 8l, and the idle portion of. the

chain is returned below the rib 84.

It will be observed that, when shaft 50 is elevated by manipulation of handle -51, the gear 80 on the upper end of the shaft will be raised out of engagement with the rack 8|. At such time the horizontal slide will be free to roll horizontally upon the rotary table. A handle 88, shown best in Figures 1 and 3, is provided in order that assenso the operator may readily move the horizontal slide back and lforth on the roller chain, as is required in sharpening surface breaches. The han-V die 88 for moving` the horizontal. slide 82 backward and forward is connected to a shaft |00 Journaled in the horizontal slide 82. The shaft |08 extends through a vertically sliding block |01 having an upwardly projecting threaded stud |08. A nut |08, threaded on the stud |00 and bearing against a washer H0, may be tightened lto pull the sliding block upwardly and hence clamp the shaft |00 and, consequently, the handle 88 against rotation. This means is provided to adjust the position of the handie- 88 to suit the convenience of the operator.

As best shown in Figure 2, a pair of adjustable stops are secured to the side of the horizontal slide 82. The stops 88 are adiustablelongitudinally'of the slide by means of a T-slot 8| andare held in adjusted position in the usual manner, as

by nuts 82. The adjustable stops 80 are adapted zontal slide 82. A stud 88, threaded into thev wheel support and provided witha pair of nuts 89, holds the wheel support in position, with the annular surface I0| on the `forward face 'of the horizontal slide `02 slidably engaging an annular ring |02' xed to the wheel support 85. The rotary wheel support 85 may be held in adjusted position by any suitable means, such as a set screw connected to a handle lill. shown in Figure 3. The set screw is threaded through the side wall of the horizontal slide 82 and into engagement with the cylindrical projection 88 of the rotary wheel support 85.

The rotary wheel support 85V contains an electric motor H2 having a shaft ill journaled in suitable hearings, not shown, and a grinding wheel shaft ||5 extending parallel to the motor shaft IH and journaled in anti-friction bearings H8. A grinding Wheel is mounted on the projecting end of the shaft I5.

As best shown in Figure 3a, which is a side elevation of the rotary wheel supporting member, the grindingwheel shaft H5 is driven from the motor shaft H4 by means of a pair of pulleys |20 and |2| connected by a belt |22. The pulleys are removably secured upon their respective shafts by means of' nuts |28 and |24. The belt and pulleys are enclosed within a removable housing section or cover |25. The beltdrive is employed in order to permit change in the speed ratio between the two shafts. When sharpening very small diameter tround broaches, it is neces-A sary to employ a grinding wheel of very small diameter to avoid interference with the tooth face. Consequently, in order to obtain the most efllcient cutting speed for the small grinding wheel it is necessary to drive the grinding wheel shaft ,at a higher rate of speed than when employing a larger wheel. The necessary change'in speed ratio may be readily accomplished by changing the pulleys on the shafts ill and H5.

In Figures 4 and. 7 to 9, the means for selec-v tively operating the worm wheels 28 and 44 is best shown. Referring to Figure ,'I, the left-hand end of the hollow shaft 25 is formed as a dog clutch having -two diametrically opposed recesses |30 (only one of which appears in Figure 7) adapted to co-operate with a dog clutch ring |3| fixed, by means of a pin |32, to a shaft |33 which is journaled within the hollow shafts 25 and 4|. Similarly, the right-hand end of the hollow shaft 4| is provided with a dog clutch having two diametrically opposed recses |35 adapted to cooperate with corresponding' teeth on the opposite side of the dogclutch ring |3|.l The parts are shown in Figure 7 in the position in which the dog clutch ring |3| is engaged with the hollow shaft 4Min which position rotation of shaft |33 eifectsrotation of the worm 40 and worm wheel 44 without rotating worm 25.

When the shaft |33 is shifted axially tothe right, as viewed in Figure 7, the teeth of the dog clutch ring |3| engage in the recesses |30 of the hollow shaft 28 and similarly drive the worm 25 and the worm wheel 28 without rotating worm 40. 'I'he right-hand end of the shaft |33 is se- `cured, by means of a' tapered p in |35, to a tubular shaft |31 which. in turn, is similarly connected by pin |38 to a shaft |39, which projects through a cover plate |40 .associated with an opening in the front face of the base |0. 'Ihe outer extrem- 'ity of shaft |39 carries a hand wheel |4|. Shaft |38 is provided with a pair of annular grooves |43 and |44 so positioned that when the shaft is in its innermost position, shown in Figures 4 and 7, the outer groove |44 is just inside the inner surface of the cover plate |40. The grooves |43 and |44 are adapted to cooperate with a spring pressed latch slide |45, best shown in Figures 4 and 6. The slide |46 is provided with a reduced extremity |41 adapted to it within either the groove |43 or |44, and in Figure 6 the. extremity |41 is shown engaging in the groove |44. Latch slide |45 is slidabie within a U-shaped bracket |50 secured to the inner face of cover plate |40 in any suitable manner, as by cap screws A spring |52, received withina re cess in the bracket |50, bears against a pin |53 secured to the latch slide |45, thus normally urging the latch slide into engagement with one of the recesses |43 or |44. The latch slide is provided with a notch |55 adapted to receive the rounded extremity of a dog |55 sec d to a rotary stub shaft |51 joumaled in a boss |58 Cil projection 8| and a suitablescale may be provided on the ring |52 to cooperate with a marked point on the projection |5| and thusindicate the position to which the hand wheel |4| must be turned to raise .or lower the vertical slide 20 untu the axis or the grinding wheel is en the same level as the axis of a round broach mounted in the lathe centers. It will be observed that when the hand wheel is shifted to its outer position, it drives through worm 25 and worm wheel 28 the screw 28 which controls the elevation of the vertical slide 20. The dog clutch |3| has only two teeth and, consequently. can engage in only formed on the cover plate |40. A handle |59 is consequently, the shaft |33 and dog clutch ringl i.

|3| fromthe position shown in Figure 7 to the position in which the dog clutch engages the hollow shaft 26, handle |58 is rotated in `a direction to retract the latch slide |45 from notch |44, whereupon the operator may, by pullingthe hand wheel out. shifts the shafts and clutch member. Upon completion of the shifting .operation and release of handle |59, spring |52 will cause the latch slide |45 to engage in notch |43` of shaft |38 and thus hold the parts in the new position.

It will be observed that, as best shown in Figure 7, the cover plate |40 is provided with a hollow annular projection |5i, and the hand wheel is provided at its inner side with an annular ring |52 adapted to telescope within the projection lei; when the hand wheel and shaft |39 are shifted to their outer position, the annular ring 52 lies just Outside 0f the extremity 0f annular 75 The sharpening operation is carried out in the two positions. apart. A rotation of the hand wheel through 180 will shift the vertical slide sumciently to make the error in vertical position veasy to observe.- Accordingly, the scale on ring |52 may havegtwo zero points 180 apart or,vif only one is employed, the operator will be able to observe when the zero reading is displaced 180 and may, by disengaging the clutch |3| from hollow shaft 25. rotate the hand wheel |4| through 180 and re-engage the clutch.

The means for reciprocating the work table is best shown in Figures 4, 7 and 9. Immediately to the right of the hand wheel |4|, the base 0 is provided with an opening adapted to receive a gear housing |55 which is provided with a ange |55 vcorresponding in shape to the cover plate |40. Flange |55 is secured to the front of the base i0 in any suitable manner, as by bolts |51, and similar bolts are employed to secure the cover plate |40 inposition.

A shaft |59 is journaled in the housing and projects therefrom at the front to receive a hand wheel |10. The inner end of shaft |55 carries a pinion which meshes with a gear |12 on a countershaft |13 likewise Journaled in the housion |14 which meshes with a gear |15 on shaft |15 likewise journaled in the housing. Shaft |15, in turn, carries a-pinion |11 which meshes with a rack |18 fastened by means of cap screws |19 to a rib |80 formed on'the under side of the table As a result of this construction, rotation of the hand wheel |10 shifts the table ii transversely of the machine.

The operation of the machine is as follows: When it is desired to sharpen round breaches, the broach is mounted in the centers, as shown in Figure l. Steady rests are placed in position in the event that the breach is long enoughto require support intermediate its ends. Latch handle |59 is then shifted to the release position and v Thereupon, the latch handle |58 is again released and hand wheel |4| pushed inwardly to cause engagement between the clutch ring |3| and the hollow shaft 4| to effect a driving connection between the hand wheel |4| and the horizontal vtable 82. The rotating table '54 is then swung until the plane of the grinding wheel corresponds to the angle made by the face of the breach teeth, and it is clamped in that position by manipulation of handle 13. The rotary wheel support is xed in the position in which the axis of the grinding 'wheel spindle ||5 lies in a horizontal plane. The machine is then conditioned to perform the sharpening operation.

usual manner by manipulating the hand wheels l III and |10. -Thus the operator, with one hand on each hand wheel, rotates the hand wheel Ilo until the grinding wheel III is in alignment with the front face of the tooth to be sharpened, whereupon the wheel MI is rotated to feed the wheel into the tooth space, thereby removing the thin layer on the front face of the tooth. It will be observed that an accurate control of the position of the grinding wheel relative to the tooth space is provided by the two hand wheels. During the grinding operation it is to be understood, of course, that the broach will be rotated by the driven spindle unit Il.

In order to sharpen surface broaches, lever 56 is shifted to elevate shaft Sill and thereby disengage pinion 80 from rack 8|, as shown in dotted lines in Figure 5. Hand wheel MI is then pulled out to engage the clutch ring IBI with the hollow shaft 26. The rotary table El is turned until the path of movement of the horizontal slide 82 is parallel to the broach teeth. In vmost cases the broach teeth will run perpendicular to the slide I l and, consequently, the table will be rotated until the slide 82 is perpendicular to the slide II. It will then be clamped in that position. The rotary wheel support 95 is then rotated about the axis of stud 98 until the plane of the grinding wheel IIl lies in the plane of the front faces of the broach teeth, as best shown in Figure 2. After these adjustments are made, the hand wheel III is manipulated to adjust the vertical slide until the grinding wheel H1 is at the proper height to cut to the root of the teeth. The machineis then in condition to perform the sharpening operation.

The sharpening of surface broaches is effected by manually reciprocating the roller mounted horizontal slide 82, the operator grasping the handle 89 for that purpose. In this connection, the adjustable stops 90 are set to limit the reciprocation of the slide 82 at each end of the broach teeth. Between each manual reciprocation of the horizontal slide 82, the operator rotates the hand wheel Il!) to properly align the grinding wheel I Il with the tooth to be sharpened.

It will be observed that in accordance with the present invention there is provided a simple machine which may be Ieffectively used to sharpen both round and flat breaches. An important feature of the machine resides in the fact that the hand wheel |10 for operating the work slide I I is in the same position with respect to the hand less conventional positions for the primary con-- trol handles and hand wheels, those conventional positions having been found most desirable as a result of long experience.

While only one form of the invention is shown and described, it is apparent that modifications are available within the spirit of the invention and within the scope of the appended claims.

What is claimed is:

l. In a broach sharpening machine, a rotary grinding wheeL-a machine base, means mounting the grinding wheel on the base for rectilinear movement both in a horizontal path perpendicular to the wheel axis and in a vertical path and the grinding wheel on the base for rectilinear wheel I4 I which controls either the vertical slide movement both in a horizontal path perpendicular to the wheel axis and in a vertical path and rotary movement about two axes parallel, respectively, to the paths of rectilinear movement, separate means for effecting 'controlled rectilinear movement in each of said paths, said last named means including a shaft, a hand wheel for operating the shaft, a' pair of driven members freely journaled on said shaft and adapted, respectively, to eect movement of said wheel in said paths, and means for selectively clutching said driven members to said shaft.

3. In a broach sharpening machine, a rotary grinding wheel, a machine base, means mounting the grinding wheel on the base for rectilinear movement both in a horizontal path perpendicular to the wheel axis and in a vertical path and rotary movement about two axes parallel, respectively, to the paths of rectilinear movement, separate means for effecting controlled rectilinear movement in each of said paths, said last named means including an axially shiftable shaft, a hand Wheel for operating the shaft. a' pair of driven members freely journaled on said shaft and adapted, respectively, to effect movement of said wheel in said paths, and means operable on axial shifting of said shaft for selectively clutching said driven members to said shaft.

4. In a broach 'sharpening machine, a hase, a vertically movable slide mounted on the base, a rotary table journaled on said slide for movement about a vertical axis, a horizontally movable slide.

mounted on said table, a grinding wheel support rotatably mounted on said horizontally movable table for movement about an axis perpendicular to said vertical axis, a horizontal shaft joumaled on said base and a vertical shaft journaled on said base concentric with said vertical axis, a driving connection between said horizontal shaft and said concentric vertical shaft, a disengageable driving connection between said concentric vertical shaft and the horizontally movable table, and manual means for operating said horizontal shaft.

5. In a broach sharpening machine, a base, a vertically movable slide mounted on the base, a rotary table journaled on said slide for movement about a vertical axis, a horizontally movable slide mounted on said table, a grinding wheel support rotatably mounted on said horizontally `movable table for movement about an axis perpendicular to said vertical axis, a horizontal-shaft Journaled on said base and a pair of vertical shafts journaled on said base, one of said vertical shafts being concentric with said vertical axis, a selectively operative. driving connection between said horizontal shaft and said vertical shafts, a driving connection between said concentric vertical shaft and the horizontally movable table, a drivlng connection between the other vertical shaft and the vertically movable table, and manual means for operating said horizontal shaft.

HARRY H. GOTBERG. 

